Comments on bosonic super-WIMPs search experiments

TL;DR

This paper highlights the significance of the Compton-like process in super-WIMP dark matter searches, showing it surpasses absorption at higher masses and can improve experimental limits when included.

Contribution

It introduces the Compton-like process as a dominant detection mechanism for super-WIMPs above 150 keV/c^2, enhancing search sensitivity.

Findings

Compton-like process dominates absorption above 150 keV/c^2.

Cross-section for vector super-WIMPs increases by 10-100 times in 400 keV/c^2 to 1 MeV/c^2 range.

Including this process can improve experimental upper limits.

Abstract

Bosonic super-WIMPs, including pseudoscalar and vector particles, are dark matter candidates. Until now, many underground experiments searches for super-WIMPs have been performed in the mass range of a few $\rm keV/c^2$ to 1 $\rm MeV/c^2$. All these searches utilize the absorption process of a super-WIMP by a target atom in the detector, which is similar to the photoelectric effect. In this study, we consider another process, namely, a Compton-like process. As an example, we compare the cross-section of a germanium atom for the absorption process with that of a Compton-like process. Our findings indicate that the cross-section for the Compton-like process becomes dominant, compared to that for the absorption process for mass above approximately 150 $\rm keV/c^2$ for both pseudoscalar and vector super-WIMPs. In particular, the cross-section for the Compton-like process for a vector super-WIMP becomes increasingly greater than that for the absorption process by an order of magnitude to two orders of magnitude in the 400 $\rm keV/c^2$ to 1 $\rm MeV/c^2$ mass range, respectively. By including the Compton-like process, which has not been used in any other super-WIMP search experiment, the experimental upper limits can be improved.